Search

We present six deep Near-InfraRed (JHK_s) photometric catalogues of galaxies identified in six cluster candidates (VC02, VC04, VC05, VC08, VC10, VC11) within the Vela Supercluster (VSCL) as part of our efforts to learn more about this large supercluster which extends across the zone of avoidance (l=272.5 \pm 20 deg, b= \pm 10 deg, at cz~ 18000 km/s). The observations were conducted with the InfraRed Survey Facility (IRSF), a 1.4m telescope situated at the South African Astronomical Observatory (SAAO) in Sutherland. The images in each cluster cover ~ 80% of their respective Abell radii. We identified a total number of 1715 galaxies distributed over the six cluster candidates, of which only ~ 15% were previously known. We study the structures and richnesses of the six clusters out to the cluster-centric completeness radius of r_c, 18 pages, 10 Figures, 13 Tables. Accepted for publication in MNRAS

The importance of lightning has long been recognized from the point of view of climate-related phenomena. However, the detailed investigation of lightning on global scales is currently hindered by the incomplete and spatially uneven detection efficiency of ground-based global lightning detection networks and by the restricted spatio-temporal coverage of satellite observations. We are developing different methods for investigating global lightning activity based on Schumann resonance (SR) measurements. SRs are global electromagnetic resonances of the Earth-ionosphere cavity maintained by the vertical component of lightning. Since charge separation in thunderstorms is gravity-driven, charge is typically separated vertically in thunderclouds, so every lightning flash contributes to the measured SR field. This circumstance makes SR measurements very suitable for climate-related investigations. In this study, 19 days of global lightning activity in January 2019 are analyzed based on SR intensity records from 18 SR stations and the results are compared with independent lightning observations provided by ground-based (WWLLN, GLD360 and ENTLN) and satellite-based (GLM, LIS/OTD) global lightning detection. Daily average SR intensity records from different stations exhibit strong similarity in the investigated time interval. The inferred intensity of global lightning activity varies by a factor of 2-3 on the time scale of 3-5 days which we attribute to continental-scale temperature changes related to cold air outbreaks from polar regions. While our results demonstrate that the SR phenomenon is a powerful tool to investigate global lightning, it is also clear that currently available technology limits the detailed quantitative evaluation of lightning activity on continental scales.

We present WALLABY pilot data release 1, the first public release of HI pilot survey data from the Wide-field ASKAP L-band Legacy All-sky Blind Survey (WALLABY) on the Australian Square Kilometre Array Pathfinder. Phase 1 of the WALLABY pilot survey targeted three $60~{\rm deg}^2$ regions on the sky in the direction of the Hydra and Norma galaxy clusters and the NGC 4636 galaxy group, covering the redshift range of z < 0.08. The source catalogue, images and spectra of nearly 600 extragalactic HI detections and kinematic models for 109 spatially resolved galaxies are available. As the pilot survey targeted regions containing nearby group and cluster environments, the median redshift of the sample of z ~ 0.014 is relatively low compared to the full WALLABY survey. The median galaxy HI mass is $2.3 \times 10^{9}~M_{\odot}$. The target noise level of 1.6 mJy per $30''$ beam and 18.5 kHz channel translates into a $5\sigma$ HI mass sensitivity for point sources of about $5.2 \times 10^{8} \, (D_{\rm L} / \mathrm{100~Mpc})^{2} \, M_{\odot}$ across 50 spectral channels (~200 km/s) and a $5\sigma$ HI column density sensitivity of about $8.6 \times 10^{19} \, (1 + z)^{4}~\mathrm{cm}^{-2}$ across 5 channels (~20 km/s) for emission filling the $30''$ beam. As expected for a pilot survey, several technical issues and artefacts are still affecting the data quality. Most notably, there are systematic flux errors of up to several 10% caused by uncertainties about the exact size and shape of each of the primary beams as well as the presence of sidelobes due to the finite deconvolution threshold. In addition, artefacts such as residual continuum emission and bandpass ripples have affected some of the data. The pilot survey has been highly successful in uncovering such technical problems, most of which are expected to be addressed and rectified before the start of the full WALLABY survey., Comment: 24 pages, 13 figures, 5 tables, accepted for publication in PASA

Introduction: HIV-associated neurocognitive disorders (HAND) are a spectrum of cognitive impairments occurring in chronic HIV infection. HAND are highly prevalent in sub-Saharan Africa (SSA), despite combination antiretroviral therapy (cART). Older people appear to be at increased risk. Cognitive reserve (CR), shown to be protective in neurodegenerative dementias, may also protect against HAND.Aim: To evaluate the association of CR and risk of HAND in an older cART-treated population in SSA.Methods: This was a cross-sectional observational study undertaken at hospital outpatient clinics in Mbeya, Southwest Tanzania. HIV-positive participants aged ≥ 50 years and established on cART underwent diagnostic assessment by operationalised AAN criteria. Assessment included neuropsychological test battery, functional assessment, informant history and depression screen. HIV-negative control participants were attendees of other chronic disease clinics who completed neuropsychological assessments to provide normative scores for HAND diagnosis. CR was measured using the Cognitive Reserve Index (CRI) and other proxy measures including years of formal education.Results: Lower total Cognitive Reserve Index (CRI) score, lack of formal education, unemployment and low-skilled manual work were associated with increased risk of HAND. Lower CRI score and lack of formal education were independent risk factors for HAND but HIV disease severity measures were not.Conclusion: Higher total CRI score and formal education appeared to be protective for HAND, in this cohort. These are potentially modifiable factors, though education may be difficult to modify in later life. Cognitive reserve may be more important than HIV-disease control in risk of HAND in older people with treated HIV.

Agriculture is the backbone of Indian economy. Mostly crops are loss due to the erroneous selection of the crop, climate change. The farmers are generally not aware of the requirements of the crops. i.e. The minerals, soil moisture & other soil requirements one more problem that a farmer generally encounters is the pest & diseases that can affect the crops they grow which they are generally unaware of in an early stage. This are the problems of farmer is addressed in our paper and we have tried to solve it with the help of Agro Expert using Google API system by the help of our model. We predict the suitable crop to the farmers and also detect the pest and may affect as suggest the pest control technique. In this paper we have applied collaborative filtering algorithm, aprori algorithm, linear regration prediction technique.

The U.S. National Lightning Detection Network (NLDN) underwent a complete sensor upgrade in 2013 followed by a central processor upgrade in 2015. These upgrades produced about a factor-of-5 improvement in the detection efficiency of cloud lightning flashes and about one additional cloud pulse geolocated per flash. However, they also reaggravated a historical problem with the tendency to misclassify a population of low-current positive discharges as cloud-to-ground strokes when, in fact, most are probably cloud pulses. Furthermore, less than 0.1% of events were poorly geolocated because the contributing sensor data were either improperly associated or simply underutilized by the geolocation algorithm. To address these issues, Vaisala developed additional improvements to the central processing system, which became operational on 7 November 2018. This paper describes updates to the NLDN between 2013 and 2018 and then focuses on the effects of classification algorithm changes and a simple means to normalize classification across upgrades.

This study explores the causes of a severe thunderstorm outbreak north of 70°N on 24–25 July 2014 and provides the first characterization of lightning over the Canadian Arctic Islands. Lightning da...

Terrestrial gamma ray flashes (TGFs) are a class of enigmatic electrical discharges in the Earth’s atmosphere. In this study, we analyze an unprecedentedly large dataset comprised of 2188 TGFs whose signatures were simultaneously measured using space- and ground-based detectors over a five-year period. The Gamma-ray Burst Monitor (GBM) on board the Fermi spacecraft provided the energetic radiation measurements. Radio frequency (RF) measurements were obtained from the Global Lightning Dataset (GLD360). Here we show the existence of two categories of TGFs − those that were accompanied by quasi-simultaneous electromagnetic pulses (EMPs) detected by the GLD360 and those without such simultaneous EMPs. We examined, for the first time, the dependence of the TGF-associated EMP-peak-amplitude on the horizontal offset distance between the Fermi spacecraft and the TGF source. TGFs detected by the GBM with sources at farther horizontal distances are expected to be intrinsically brighter and were found to be associated with EMPs having larger median peak-amplitudes. This provides independent evidence that the EMPs and TGFs are produced by the same phenomenon, rather than the EMPs being from “regular” lightning in TGF-producing thunderstorms.

After decades of research, our understanding of when and why individuals infected with Plasmodium falciparum develop clinical malaria is still limited. Correlates of immune protection are often sought through prospective cohort studies, where measured host factors are correlated against the incidence of clinical disease over a set period of time. However, robustly inferring individual-level protection from these population-level findings has proved difficult due to small effect sizes and high levels of variance underlying such data. In order to better understand the nature of these inter-individual variations, we analysed the long-term malaria epidemiology of children ≤12 years old growing up under seasonal exposure to the parasite in the sub-location of Junju, Kenya. Despite the cohort’s limited geographic expanse (ca. 3km x 10km), our data reveal a high degree of spatial and temporal variability in malaria prevalence and incidence rates, causing individuals to experience varying levels of exposure to the parasite at different times during their life. Analysing individual-level infection histories further reveal an unexpectedly high variability in the rate at which children experience clinical malaria episodes. Besides exposure to the parasite, measured as disease prevalence in the surrounding area, we find that the birth time of year has an independent effect on the individual’s risk of experiencing a clinical episode. Furthermore, our analyses reveal that those children with a history of an above average number of episodes are more likely to experience further episodes during the upcoming transmission season. These findings are indicative of phenotypic differences in the rates by which children acquire clinical protection to malaria and offer important insights into the natural variability underlying malaria epidemiology.

The progression of the SARS-CoV-2 pandemic in Africa has so far been heterogeneous and the full impact is not yet well understood. Here, we describe the genomic epidemiology using a dataset of 8746 genomes from 33 African countries and two overseas territories. We show that the epidemics in most countries were initiated by importations, predominantly from Europe, which diminished following the early introduction of international travel restrictions. As the pandemic progressed, ongoing transmission in many countries and increasing mobility led to the emergence and spread within the continent of many variants of concern and interest, such as B.1.351, B.1.525, A.23.1 and C.1.1. Although distorted by low sampling numbers and blind-spots, the findings highlight that Africa must not be left behind in the global pandemic response, otherwise it could become a breeding ground for new variants.

This chapter offers an overview of Law and Literature and explores three primary areas in which intellectual property (IP) scholarship engages with Law and Literature’s methods and tools: the creation of objects that give rise to rights; the definition and enforcement of those rights and their limits; and the narrative of progress and revisionist theories of the field. IP concerns intangible constructs: works, inventions, secrets, marks, or personas. IP ownership implicates theories of representation given the symbolic nature of IP rights to the things they protect, and determining the scope of protection almost always entails multiple interpretive steps. Hence theories of representation and interpretation are relevant to defining the work, assessing the scope of protection, and conducting infringement analysis. Lastly, Law and Literature offers larger narratives about IP that centre on values, history, textuality, theory, culture, context, selfhood, or community. Law and Literature has helped broaden beyond the narrow utilitarian framing of the received approach to IP and thus provided disciplinary cover for pluralistic accounts of the field to emerge. In this revisionism, the three main strands of Law and Literature—which centre on practical wisdom, interpretation, and narrative—offer diverse alternatives for measuring progress or evaluating the IP system in broader sociological and constitutional context.

The linear regression model with normal distribution errors in detecting change in the regression parameters β0 and β1 has been studied. We propose a testing procedure based on a modified informati...

Background: Studies of long-term malaria cohorts have provided essential insights into how Plasmodium falciparum interacts with humans, and influences the development of antimalarial immunity. Immunity to malaria is acquired gradually after multiple infections, some of which present with clinical symptoms. However, there is considerable variation in the number of clinical episodes experienced by children of the same age within the same cohort. Understanding this variation in clinical symptoms and how it relates to the development of naturally acquired immunity is crucial in identifying how and when some children stop experiencing further malaria episodes. Where variability in clinical episodes may result from different rates of acquisition of immunity, or from variable exposure to the parasite. Methods: Using data from a longitudinal cohort of children residing in an area of moderate P. falciparum transmission in Kilifi district, Kenya, we fitted cumulative episode curves as monotonic-increasing splines, to 56 children under surveillance for malaria from the age of 5 to 15. Results: There was large variability in the accumulation of numbers of clinical malaria episodes experienced by the children, despite being of similar age and living in the same general location. One group of children from a particular sub-region of the cohort stopped accumulating clinical malaria episodes earlier than other children in the study. Despite lack of further clinical episodes of malaria, these children had higher asymptomatic parasite densities and higher antibody titres to a panel of P. falciparum blood-stage antigens. Conclusions: This suggests development of clinical immunity rather than lack of exposure to the parasite, and supports the view that this immunity to malaria disease is maintained by a greater exposure to P. falciparum, and thus higher parasite burdens. Our study illustrates the complexity of anti-malaria immunity and underscores the need for analyses which can sufficiently reflect the heterogeneity within endemic populations.

Tambora Field reservoir zone is sub-divided into D, E, F and G. Of the four zonation, Tambora G Zone has the lowest recovery factor. Based on this, the current study was intended to have better understanding of the diagenetic processes in low productivity reservoirs and its development strategy in that zone. Reduction of porosity and permeability due to different diagenetic intensity and causes are possible reasons for this condition. A new-improved petrology study was performed to understand the effects of diagenesis and the contribution of clay minerals which has led to worsening reservoir characteristics. In order to achieve better understanding of reservoir characteristics, integrated petrology analysis of petrography, XRD, SEM and CEC were performed. The results of detailed lithofacies analyses show that low productivity related to poor porosity and permeability is primarily caused by mechanical compaction and are worsened by chemical diagenesis related to isolated pore spaces, unconnected pore throats and depositional environment. Those affects the increase of diagenetic quartz-overgrowths, ferroan/iron-bearing and calcareous minerals. The occurrence of these minerals act as a pore-filling cement and are more developed in clean rather than shaly Sandstones. The most dominant diagenetic clay mineral in all lithofacies is recorded as kaolinite, followed by illite, chlorite and illite-smectite with this trend varying relative to depth and lithofacies. The effect of these factors is more intense when burial depth increases, and the depositional environment is increasingly distal as in the G Zone’s northeast area. Referring to this, and in order to minimize the risks of diagenetic minerals causing low productivity, the well placement strategy is addressed to the south and northwest compared to the northeast area. The proven result of applying this approach is the success story of drilling the TM-132 northwest well in 2019 that reached an initial gas rate production of around 3 MMscfd.

The 2016–2017 shallow submarine eruption of Bogoslof volcano in Alaska injected plumes of ash and seawater to maximum heights of ~ 12 km. More than 4550 volcanic lightning strokes were detected by the World Wide Lightning Location Network (WWLLN) and Vaisala’s Global Lightning Dataset (GLD360) over 9 months. Lightning assisted monitoring efforts by confirming ash-producing explosions in near-real time, but only 32 out of the 70 explosive events produced detectable lightning. What led to electrical activity within some of the volcanic plumes, but not others? And why did the lightning intensity wax and wane over the lifetime of individual explosions? We address these questions using multiparametric observations from ground-based lightning sensors, satellite imagery, photographs, acoustic signals, and 1D plume modeling. Detailed time-series of monitoring data show that the plumes did not produce detectable lightning until they rose higher than the atmospheric freezing level (approximated by − 20 °C temperatures). For example, on 28 May 2017 (event 40), the delayed onset of lightning coincides with modeled ice formation in upper levels of the plume. Model results suggest that microphysical conditions inside the plume rivaled those of severe thunderstorms, with liquid water contents > 5 g m−3 and vigorous updrafts > 40 m s−1 in the mixed-phase region where liquid water and ice coexist. Based on these findings, we infer that ‘thunderstorm-style’ collisional ice-charging catalyzed the volcanic lightning. However, charge mechanisms likely operated on a continuum, with silicate collisions dominating electrification in the near-vent region, and ice charging taking over in the upper-level plumes. A key implication of this study is that lightning during the Bogoslof eruption provided a reliable indicator of sustained, ash-rich plumes (and associated hazards) above the atmospheric freezing level.

This paper presents the findings on the study on land cover changes and their determinants in the coral rag ecosystem of the South District of Unguja. The study is based on data extracted from the 1975, 2009, and 2014 satellite images using remote sensing and geographical information systems (GIS) techniques. Additional data were collected through structured interviews in a household survey, focus group discussions, key informant interviews, transect walks and observation. The major change detected in the study area from 1975 to 2014 was the decline of forests by 28.3% from 43.31 to 15% and the increase of semi-open forest and bush by 24.16% from 10.54 to 34.7%. During the same time, settlements increased from 0.1 to 4.9%. Different factors both direct and underlying have caused land cover change in the study area. Direct causes include shifting cultivation, commercial cutting of wood for fire wood, charcoal, pegs and cutting sticks for seaweed farming, while the underlying ones are population growth, policy reform and policy failure, land tenure insecurity, soil as well as the terrain and underlying rocks. If not properly addressed, land cover changes are likely to affect either positively or negatively the wildlife as well as the livelihoods of the communities. Investment in intensive cultivation and alternative sources of energy is required to reduce over utilization of forest resources and to improve conservation and people’s livelihood. Key words: Land cover change, coral rag ecosystem, fragmentation, forest decline, Unguja Island.